Rift Valley Fever can infect both people and animals."If it ever got into the United States, our cattle industry would just go down the tank," Conlon said. On top of that, people usually contract the virus by eating infected meat.

RFV only causes death in 1% of cases but causes nasty effects nonetheless. Some vomit blood, and half who contract the ocular form will go blind. The disease hasn't breached the United States yet, but according to Conlon, we have the perfect conditions.

Symptoms: Some cases have no symptoms while others experience fever, generalized weakness, back pain, and dizziness. About 1% of cases turn hemorrhagic.

"I've been in Africa and seen and heard children just screaming for days on end because of the pain. It's a really pathetic, nasty disease," Conlon said. He added most cases are reported in the Indian ocean basin, but a few have popped up in the last couple years in Northern Italy — a climate similar to the U.S.

Florida has also seen recent outbreaks of Dengue fever, also known as break bone fever. "It feels like all the bones in your body are broken," Conlon said.

The disease becomes much more worrisome the second time around. If someone contracts a different strain again, the disease morphs into the hemorrhagic form, meaning they start bleeding from every orifice of their body. That state likely results in death, especially in children.

If anything, Dengue fever proves that mosquito-borne illnesses aren't confined to tropical areas, like many people think. In fact, the first case of the disease was discovered in Philadelphia, according to Conlon. "These diseases do very, very well in temperate climates," he added.

For every case of West Nile Virus that we see, authorities say there are at least 35 undocumented cases, according to Conlon. That means the 35,000 documented cases of West Nile since 1999 really translates into millions, he says.

Symptoms: 70 to 80% of people show no symptoms, but the rest experience headache, body aches, joint pains, vomiting, diarrhea, or rash.

Incubation: 2 to 14 days, but usually 2 to 6.

Fatality: Less than 1% develop the neuro-invasive form (encephalitis or meningitis).